Antonio Sabato Jr. Antonio Sabato Jr.

Castle is about to get a little nostalgic!

Former soap opera star Antonio Sabato Jr. will guest-star on the upcoming sixth season, has learned exclusively. He will play Ramon Russo, an actor best known for his role on the fictional '90s sitcom 2 Cool For School.

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As the cast of the Saved By the Bell-esque sitcom prepares to reunite for a movie, the Screech-like character is murdered. Enter Castle (Nathan FIllion), Ryan (Seamus Dever) and Esposito (Jon Huertas), who take on the case until a familiar face returns to lead the investigation.

Besides his soap work on General Hospital and The Bold and the Beautiful,  Sabato has appeared on such shows as CSI: NY, Rizzoli & Isles, Hot in Cleveland, and, most recently, ABC Family's Baby Daddy. Sabato is slated to appear in the new season's third episode, titled "Need to Know."

Castle's sixth season premieres Monday, Sept. 23 at 10/9c.